Like many I use my seating die to crimp in a seperate step. IMO crimping is not just to hold bullets in place under recoil but different crimps effects how the powder burns. Not so critical in longer rifle barrels but can be a deal breaker in handguns.
As for 10grs of 2400....... I assume your talkin .357M and if so that's well below starting for book. You have to watch it, some powders you can do that with, some become just as unsafe as going over book. Now I don't think that 2400 becomes unsafe (although I'm not 100% on this) but I do know it's not a powder intended for light loads and needs certain pressues to get proper burn. It's a magnum powder for magnum loads. Going below book may result in smokey, inconsistant reloads. If you want light to medium loads you need to try a different powder.
Another option if you are wanting less than magnum loads and still want to use 2400 is to load it in shorter .38sp cases.